Mounting base



FIG. 1 is an upper perspective view of a mounting base, showing my design;

FIG. 2 is a lower perspective view thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a front view thereof;

FIG. 6 is a back view thereof;

FIG. 7 is a top view thereof; and,

FIG. 8 is a bottom view thereof. 

The ornamental design for a mounting base, as shown and described. 